BingBot Crawl Activity Surging?

A WebmasterWorld thread has some SEOs and webmasters complaining that Microsoft's search engine crawler, BingBot, is crawling web sites way too eagerly.

As many of you know, spiders/crawlers can have an impact on a web server's speed. Too much crawler activity on a web site, especially with a slower web server, can result in the site slowing down or even crashing.

This is why many official spiders, like from Google or Bing, have ways to throttle their crawl based on the web server capabilities.

There are new reports from some webmasters that BingBot has stepped up its crawl rate to unusual levels. It is at a level where some webmasters are questioning if it is really Bing or someone pretending to be Bing. One webmaster said:

Over the past three days bing's crawler is giving Googlebot a run for it's money on my forum in terms of crawl rate. I triple checked to make sure the IP and user agent was legit and it is.